A conventional imaging apparatus in this category made known by Patent Document 1 has a substrate on which an imaging element is mounted, and a lens holder arranged to surround the imaging element concentrically. It further includes a lens barrel (lens holder) which is helically fitted with the inner surface of lens holder so as to be able to turn around the optical axis with respect to the imaging element, and the lens barrel moves along the direction of optical axis by such turning. An imaging lens is fitted in the inside of the lens barrel to have the image of an object focused on the imaging element.
The lens barrel and the lens holder are provided, respectively, with screwed arrangements; focusing is adjusted by turning the lens barrel.
Patent Document 2 discloses an elastic member for preventing rattling of the lens barrel fitted with imaging lens in the optical axis direction. The elastic member is a sort of spring washer, which shows a ring-shape when viewed from the above, while at the side view a waving form.
In the imaging apparatus as disclosed in Patent Document 1, however, screwed arrangements have to be provided on both the lens barrel and the lens holder. This implies an increased cost for die making. Furthermore, in the assembly stage of coupling the lens holder and the lens barrel together, an operator has to turn the lens holder and/or the lens barrel. This type of operation is an adverse factor for the improvement of manufacturing productivity.
As to the imaging apparatus disclosed in Patent Document 2, it necessitates an elastic member for preventing a rattling with the lens barrel moving in the optical axis direction. This means that a certain space for the elastic member has to be provided in the optical axis direction; this is a factor against the ongoing effort for further downsizing and slimming. The number of piece parts counts also increases.                Patent Document 1: Japanese Patent Unexamined Publication No. 2005-128578        Patent Document 2: Japanese Patent Unexamined Publication No. 2006-30893        